The present invention relates to a cosmetic or pharmaceutical composition for application to the skin, containing a compound capable of releasing two active substances by action of two enzymatic activities, the activities of glucocerebrosidase and esterase, starting with a glucoconjugate.
It has been confirmed after overexpression of cutaneous xcex2-glucocerebrosidase that this enzyme is indeed capable of recognizing and hydrolyzing such glucoconjugates, thus allowing a slow release of the active substance, without an accumulation effect.
The bioprecursor strategy has been used previously for the release of active agents in two previous cases:
release of retinol from its ester with palmitic acid under the action of the esterase activity of the skin (J. Boenlein, et al. Characterization of esterase and alcohol dehydrogenase activity in skin. Metabolism of retinyl palmitate to retinol (Vitamin A) during percutaneous absorption. Pharm. Res. 11, 1155-1159 (1994);
release of vitamin C from a glucoconjugate under the action in this case of a glucosidase activity (patent FR-2 715 565).
Retinoic derivatives are nowadays used in dermatology in various indications, for instance psoriasis or ichthyosis, or alternatively to obtain a depigmentation of the skin (reduction in melanogenesis due to the action of vitamin A); applications to combat ageing of the skin are also sought.
However, the topical use of retinoic derivatives comes up against a certain number of difficulties, due to the lack of stability over time and the lack of stability to light of these derivatives, the irritation resulting from local overconcentrations and also from a poor penetration of these derivatives through the horny layer. This drawback is due to the highly lipophilic nature of the substance which, when deposited on the skin, is in fact largely removed by desquamation. Moreover, side effects (appearance of redness, irritation, oedema and excessive desquamation) limit its use to patients in urgent need, such as those afflicted with persistent acne.
This consequently explains the advantage of the present invention for improving the bioavailability of the active agent in the form of a glucose-spacer-active agent ternary complex, with facilitated penetration and hence the ability to be used in small amount, thus avoiding the harmful effects of local overconcentrations, which are responsible for intolerances.
The present invention relates to a ternary glucosyl complex, which is a bioprecursor of at least one retinoic active principle, in particular retinoic acid, intended for percutaneous application, of formula (I) 
in which:
E represents a linear, branched or cyclized hydrocarbon-based spacer group of aliphatic or aromatic nature which may contain one or more oxygen hetero atoms and which may bear one or more carbonyl groups,
A represents a residue of a molecule of said retinoic active principle, linked to the spacer group via a carboxylate function,
n=1 or 2.
According to another characteristic of the invention, in the complex of formula I, the group E represents a group which has a complementary pharmaceutical and/or cosmetic activity, in particular which has a moisturizing, depigmenting and/or antibacterial activity.
In particular, the group E can represent a group derived from L or D glycerol, hydroquinone or flavonoids, in particular flavonoids of natural origin.